The high levels of insulin and insulin-resistance that accompany diabetes are often associated with fatty liver or hepatic steatosis, an untreatable condition that can lead to chronic liver disease and death. In this condition, large lipid-filled compartments accumulate in the cells of the liver due to an increase in production of fatty acids in the liver. The end result is an enlarged liver.
Following up research that indicated that eating soy protein reduces lipid production and prevents hyperinsulinemia (the loss of effectiveness of insulin), Dr. Nimbe Torres, of the Instituto Nacional de Ciencias Medicas y Nutricion in Mexico, investigated the effects of a diet high in soy protein on the development of fatty liver associated with diabetes.
Dr. Torres fed Zucker diabetic fatty rats that develop hyperinsulinemia and hepatic steatosis a diet of soy protein for 160 days. She found that the consumption of soy protein prevented the accumulation of triglycerides and cholesterol in the liver despite the development of obesity and hyperinsulinemia in the rats.
"We also observed that the effects of soy protein were due to a low expression of genes involved in the synthesis of fatty acids and triglycerides in the liver," explained Dr. Torres. "These changes were due to a reduction in the transcription factors that control the expression of genes involved in lipid production."
In addition, levels of a transcription factor involved in controlling genes involved in fatty acid breakdown, as well as its target genes, were increased in rats fed soy protein. Thus, feeding rats a soy-rich diet reduced the amount of fatty acid in their liver by not only reducing lipid production but also by increasing its breakdown.
Although further research is needed, Dr. Torres believes that consuming soy protein could very well reduce insulin resistance, renal damage, and fatty liver, improving quality of life.
The American Society for Biochemistry and Molecular Biology (ASBMB) is a nonprofit scientific and educational organization with over 11,000 members in the United States and internationally. Most members teach and conduct research at colleges and universities. Others conduct research in various government laboratories, nonprofit research institutions, and industry.
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The manuscript for the Journal of Lipid Research paper can be downloaded from the following URL: